1. Field of the Invention
The present invention relates to a power control apparatus and an electrically powered vehicle, and more specifically to power control at the time of regenerative braking of an electrically powered vehicle.
2. Description of the Background Art
In an electrically powered vehicle such as an electric vehicle or a hybrid vehicle that runs using a motor as a power source, at the time of braking of the vehicle, regenerative braking is generally done, in which the motor is rotated by the rotating force from the driving wheel to regenerate power, and the braking force corresponding to the regenerated power is used as the braking force of the vehicle.
When the vehicle is running on a long, downward slope at a high speed, for example, and the regenerated power increases to exceed an amount acceptable by a battery, an electric apparatus such as the battery or an inverter may be affected.
In view of the foregoing, Japanese Patent Laying-Open No. 2004-254465 discloses a regenerative braking apparatus in which surplus power generated at the time of regenerative braking is appropriately processed, to prevent adverse effect on the battery. In the regenerative braking apparatus, when surplus power is generated exceeding suitable charging power of the battery as a result of regenerative braking, a surplus power consuming load is selected from a plurality of electric loads in accordance with the magnitude of the surplus power, and the surplus power is consumed by the selected surplus power consuming load.
In the regenerative braking apparatus, the surplus power can be consumed without causing such problems that when the electric load to which the surplus power is to be cast off is already in operation and the surplus power cannot be used up, or that an electric load used only for consuming the surplus power must be provided. As a result, adverse effect on the battery can be prevented by a simple structure.
The regenerative braking apparatus disclosed in Japanese Patent Laying-Open No. 2004-254465, however, simply combines electric loads in accordance with the magnitude of surplus power, and it is impossible to successively control the amount of power consumption by the surplus power consuming loads in accordance with the magnitude of the surplus power. Therefore, it is still possible that the surplus power cannot sufficiently be used up, or excessive power might be wasted.